There is little question that cigarette smoking remains one of the nation's most significant and pressing public health concerns. Not only does smoking cost over $96 billion in public and private health care dollars annually, it is responsible for nearly half a million deaths each year. Moreover, for every tobacco related death, there are 20 individuals who are suffering with a tobacco-related disease. Nevertheless, despite research as well as financial and policy efforts geared towards tobacco prevention and cessation, the rates of smoking have remained stable for the last several years. Nevertheless, especially with regard to youth smokers, there continues to be both a significant need and a significant demand for effective cessation programs. Unfortunately, however, there is limited evidence regarding successful youth smoking cessation programs. Because so few programs have been successful, relatively little is known about the socio-demographic, psychological, and contextual characteristics of those teens who undertake structured cessation programs and how these characteristics combine to influence to cessation success or failure. Lack of such knowledge is important because in order to match interventions with those who are most likely to benefit from such programs, as well as to modify existing treatments for those who fail in established interventions, we must first understand the characteristics of those individuals and programs that succeed and those that fail. The present study seeks to address these issues by conducting extensive higher-order analyses, including structural equation modeling and hierarchical linear modeling, of the largest database of teen smokers undergoing cessation treatment in a single, empirically supported intervention - the American Lung Association's Not On Tobacco (NOT) program. By recognizing and attending to the nested nature teen smoking and teen smoking cessation, it is our hope to connect distinct ecological and individual-level variables that influence smoking cessation; thereby illuminating the complex interplay between individual smokers and both his/her proximal and distal social ecology. The contribution of the present study will be significant because it will be the first to evaluate a large database of adolescents seeking to quit smoking through a single empirically supported structured intervention. The results of the proposed study will help determine the role of individual factors (e.g., smoking history, nicotine dependence) as well as several nested factors, including peer smoking environment, cessation group dynamics, and school, community and state level factors. Such knowledge will be critical in the identification of youth at-risk for treatment failure, as well as the identification of critical contextual and policy factors at the individual, local and state level that may relate to smoking cessation success or failure. Project Narrative The proposed study is an extensive analysis of a multiple levels of influence on teen smoking cessation. The state-of-the-art statistical analyses, including structural equation modeling and hierarchical linear modeling, will help illuminate how individual factors, parental and peer influences and school, county and state factors combine to impact the outcomes of teens seeking to quit smoking through an empirically supported cessation program. The proposed research has relevance to public health and cancer control because of the potential that this research has to guide smoking cessation recruitment, program modification, and school, county and state-wide polices regarding smoking.